1. Field of the Invention
The present invention relates generally to a mobile communication system, and more particularly to an apparatus and method for efficiently managing radio resources in a mobile communication system.
2. Description of the Related Art
In a next generation 4th generation mobile communication system, a goal is for users to be provided with services having various Qualities of Service (hereinafter QoS) at a transmission speed of about 100 Mbps.
The 4th generation mobile communication system employs an Orthogonal Frequency Division Multiplexing (hereinafter OFDM) scheme which is useful for high-speed data communication in a wired or wireless channel. The OFDM scheme, one of data transmission schemes using a multi-carrier, is a type of Multi-Carrier Modulation (hereinafter MCM) scheme in which a serial input symbol stream is converted into parallel signals which are modulated with multiple orthogonal subcarriers having mutual orthogonality, and then the modulated signals are transmitted.
The 4th generation mobile communication system considers both aspects of software and hardware. That is, the 4th generation mobile communication system aims to develop more software contents, and a wireless access scheme with high spectrum efficiency and optimal QoS, as to hardware.
It is well-known in the art that factors impeding a high-speed, high-quality data service mostly originate from a channel environment in radio communication. It is a common that a channel environment in radio communication varies due to such factors as Additive White Gaussian Noise (AWGN), a fading-caused change in the power of a received signal, shadowing, Doppler effects occurring according to the movement and frequent velocity change of a terminal, and interference from other terminals and multipath signals.
To remedy these factors, the 4th generation mobile communication system copes with variations in a channel environment by adaptively applying, for example, an Adaptive Modulation and Coding (hereinafter AMC) scheme, a Hybrid Automatic Retransmission ReQuest (hereinafter HARQ) scheme, and a Multiple Input Multiple Output (hereinafter MIMO) scheme, and thus can improve the overall system performance.
However, the lack of radio resources, which is a fundamental problem in radio communication, cannot be solved even when the mobile communication systems use any of the various aforementioned schemes. Therefore, there is a need for a new method in which to solve the problem of lack of radio resources, and yet provide a QoS level of real-time traffic required by a mobile station.